1. Field of the Invention
This invention relates to substrates for use in growing mushrooms and methods of increasing the growth rate of mushrooms. Specifically, functional substrates having desirable compounds can be used to grow mushrooms, to increase the levels of these compounds in mushrooms and to improve the growth rate of the mushrooms. Additionally, functional substrates increase the potency of naturally occurring compounds already present in the mushrooms.
2. Background Information
In the commercial method of producing mushrooms, a suitably prepared substrate such as corn, rice, millet or rye is impregnated with mushroom spores or previously collected mushroom mycelia. Under sterile lab conditions, the spores or mycelia are injected into the substrate, which has been prepared by soaking the grain in water and sterilizing it. Mycelia are the filamentous hyphen of a mushroom that collect water and nutrients to enable mushrooms to grow. The grains are incubated to promote full colonization of the mycelia, at which point the mycelia-laced grains are known as “spawn”. Spawning is usually done in a plurality of individual spawn bags. The substrate provides the nutrients necessary for mycelium growth. The mycelium-impregnated substrate is then allowed to develop under carefully controlled conditions of temperature and moisture, until the hyphen of the mycelium have permeated the substrate. This process usually takes anywhere from three to four weeks for the mycelium to fully colonize the spawn bag. The spawn bag is allowed to continue to grow until the mycelium enriched product can be harvested between four to eight weeks from the beginning of the process. Typically, mushroom growers purchase spawn or grow it themselves from agar plates, as will be known to one skilled in the art. In the commercial production of medicinal mushrooms, the spawn bag is the final product, which is then sold or the contents processed into dry powdered product.
Many mushrooms are known to have medicinal properties. For example, the mistake mushroom (Grifola frondosa) contains grifolan, an important beta-glucan polysaccharide and has been shown to activate macrophages, an important component of the immune system. Laboratory studies have shown that mistake extract can block the growth of cancer tumors and boost the immune function of mice with cancer.
It has also been found that shiitake mushrooms possess beneficial properties. A specific amino acid in shiitake helps speed up the processing of cholesterol in the liver. Shiitake also appears to be a formidable cancer fighter. A polysaccharide compound called lentinan has been isolated from shiitake, and in laboratory trials, lentinan appears to stimulate immune-system cells to clear the body of tumor cells. Shiitake appears to be effective against some of the more serious viruses, such as HIV and hepatitis B.
Reishi mushrooms have been used in China and Japan for years as a medicine for liver disorders, hypertension, and arthritis, and researchers have found that reishi has anti-allergic, anti-inflammatory, anti-viral, anti-bacterial, and antioxidant properties. In vitro experiments also indicate that reishi may help fight cancer tumors.
U.S. Pat. No. 6,747,065 describes methods of producing mushroom mycelia rich in trace minerals by culturing the mycelia in a broth to which supplements have been added.
It would be desirable to improve or enhance the medicinal properties of these and other mushrooms, and shorten the growing time for commercial purposes.